1. Field of the Invention
This invention relates generally to thermometers, and more particularly to thermometers adapted for immersion in liquids.
2. Description of the Prior Art
It is desirable to know the temperature of water in which people will sit, swim, and bathe. Hot tubs, for example, can be dangerous if the temperature of the water is too high. Swimming pools are uncomfortable if the water temperature is not proper. It is desirable to know the temperature of bath water for the safety and comfort of children. Thermometers of one sort or another have in the past been used in these settings. Some of these are designed to be placed into the water for a short period of time until the thermometer has attained a steady reading. The thermometer is then removed from the water, its temperature is read, and it is set aside for later use. These thermometers cannot be left in the water owing to their fragile nature and the danger of broken glass, mercury contamination and the like.
Attempts have been made to provide thermometers which are designed to remain in the water. These thermometers can be complicated and expensive owing to the numerous seals and magnification aids that must be provided. They often cannot withstand the very rugged wear brought about by playful activity in the swimming pool or bathtub. Metal thermometers may rust. Other thermometers lose their calibration when jarred and become useless. Thermometers sometimes must be mounted in a permanent position, and are not adaptable to a variety of locations. These thermometers cannot be removed from the water for easy reading. Thermometers will sometimes quickly lose their temperature reading when removed from the water because they quickly exchange heat with the surrounding atmosphere.